test_imports.py

import pytest

from optuna._imports import try_import


def test_try_import_is_successful() -> None:
    with try_import() as imports:
        pass
    assert imports.is_successful()
    imports.check()


def test_try_import_is_successful_other_error() -> None:
    with pytest.raises(NotImplementedError):
        with try_import() as imports:
            raise NotImplementedError
    assert imports.is_successful()  # No imports failed so `imports` is successful.
    imports.check()


def test_try_import_not_successful() -> None:
    with try_import() as imports:
        raise ImportError
    assert not imports.is_successful()
    with pytest.raises(ImportError):
        imports.check()

    with try_import() as imports:
        raise SyntaxError
    assert not imports.is_successful()
    with pytest.raises(ImportError):
        imports.check()